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Code Issues Releases Wiki Activity

Rewrite AlbumArtCache to make use of coroutines instead of AsyncTask.

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Isira Seneviratne 2020-07-07 19:23:44 +05:30 committed by Philip Cohn-Cort
parent e4774b5d17
commit 7c25fa64a1
2 changed files with 451 additions and 499 deletions
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499
src/org/kde/kdeconnect/Plugins/MprisPlugin/AlbumArtCache.java
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/*
* Copyright 2017 Matthijs Tijink <matthijstijink@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License or (at your option) version 3 or any later version
* accepted by the membership of KDE e.V. (or its successor approved
* by the membership of KDE e.V.), which shall act as a proxy
* defined in Section 14 of version 3 of the license.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.kde.kdeconnect.Plugins.MprisPlugin;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.os.AsyncTask;
import android.text.TextUtils;
import android.util.Log;
import androidx.collection.LruCache;
import androidx.core.content.ContextCompat;
import androidx.core.net.ConnectivityManagerCompat;
import com.jakewharton.disklrucache.DiskLruCache;
import org.kde.kdeconnect.NetworkPacket;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
/**
* Handles the cache for album art
*/
final class AlbumArtCache {
private static final class MemoryCacheItem {
boolean failedFetch;
Bitmap albumArt;
}
/**
* An in-memory cache for album art bitmaps. Holds at most 10 entries (to prevent too much memory usage)
* Also remembers failure to fetch urls.
*/
private static final LruCache<String, MemoryCacheItem> memoryCache = new LruCache<>(10);
/**
* An on-disk cache for album art bitmaps.
*/
private static DiskLruCache diskCache;
/**
* Used to check if the connection is metered
*/
private static ConnectivityManager connectivityManager;
/**
* A list of urls yet to be fetched.
*/
private static final ArrayList<URL> fetchUrlList = new ArrayList<>();
/**
* A list of urls currently being fetched
*/
private static final ArrayList<URL> isFetchingList = new ArrayList<>();
/**
* A integer indicating how many fetches are in progress.
*/
private static int numFetching = 0;
/**
* A list of plugins to notify on fetched album art
*/
private static final ArrayList<MprisPlugin> registeredPlugins = new ArrayList<>();
/**
* Initializes the disk cache. Needs to be called at least once before trying to use the cache
*
* @param context The context
*/
static void initializeDiskCache(Context context) {
if (diskCache != null) return;
File cacheDir = new File(context.getCacheDir(), "album_art");
int versionCode;
try {
PackageInfo info = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
versionCode = info.versionCode;
//Initialize the disk cache with a limit of 5 MB storage (fits ~830 images, taking Spotify as reference)
diskCache = DiskLruCache.open(cacheDir, versionCode, 1, 1000 * 1000 * 5);
} catch (PackageManager.NameNotFoundException e) {
throw new AssertionError(e);
} catch (IOException e) {
Log.e("KDE/Mpris/AlbumArtCache", "Could not open the album art disk cache!", e);
}
connectivityManager = ContextCompat.getSystemService(context.getApplicationContext(),
ConnectivityManager.class);
}
/**
* Registers a mpris plugin, such that it gets notified of fetched album art
*
* @param mpris The mpris plugin
*/
static void registerPlugin(MprisPlugin mpris) {
registeredPlugins.add(mpris);
}
/**
* Deregister a mpris plugin
*
* @param mpris The mpris plugin
*/
static void deregisterPlugin(MprisPlugin mpris) {
registeredPlugins.remove(mpris);
}
/**
* Get the album art for the given url. Currently only handles http(s) urls.
* If it's not in the cache, will initiate a request to fetch it.
*
* @param albumUrl The album art url
* @return A bitmap for the album art. Can be null if not (yet) found
*/
static Bitmap getAlbumArt(String albumUrl, MprisPlugin plugin, String player) {
//If the url is invalid, return "no album art"
if (TextUtils.isEmpty(albumUrl)) {
return null;
}
URL url;
try {
url = new URL(albumUrl);
} catch (MalformedURLException e) {
//Invalid url, so just return "no album art"
//Shouldn't happen (checked on receival of the url), but just to be sure
return null;
}
//We currently only support http(s) and file urls
if (!url.getProtocol().equals("http") && !url.getProtocol().equals("https") && !url.getProtocol().equals("file")) {
return null;
}
//First, check the in-memory cache
if (memoryCache.get(albumUrl) != null) {
MemoryCacheItem item = memoryCache.get(albumUrl);
//Do not retry failed fetches
if (item.failedFetch) {
return null;
} else {
return item.albumArt;
}
}
//If not found, check the disk cache
if (diskCache == null) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!");
return null;
}
try {
DiskLruCache.Snapshot item = diskCache.get(urlToDiskCacheKey(albumUrl));
if (item != null) {
Bitmap result = BitmapFactory.decodeStream(item.getInputStream(0));
item.close();
MemoryCacheItem memItem = new MemoryCacheItem();
if (result != null) {
memItem.failedFetch = false;
memItem.albumArt = result;
} else {
//Invalid bitmap, so remember it as a "failed fetch" and remove it from the disk cache
memItem.failedFetch = true;
memItem.albumArt = null;
diskCache.remove(urlToDiskCacheKey(albumUrl));
Log.d("KDE/Mpris/AlbumArtCache", "Invalid image: " + albumUrl);
}
memoryCache.put(albumUrl, memItem);
return result;
}
} catch (IOException e) {
return null;
}
/* If not found, we have not tried fetching it (recently), or a fetch is in-progress.
Either way, just add it to the fetch queue and starting fetching it if no fetch is running. */
if ("file".equals(url.getProtocol())) {
//Special-case file, since we need to fetch it from the remote
if (isFetchingList.contains(url)) return null;
if (!plugin.askTransferAlbumArt(albumUrl, player)) {
//It doesn't support transferring the art, so mark it as failed in the memory cache
MemoryCacheItem cacheItem = new MemoryCacheItem();
cacheItem.failedFetch = true;
cacheItem.albumArt = null;
memoryCache.put(url.toString(), cacheItem);
}
} else {
fetchUrl(url);
}
return null;
}
/**
* Fetches an album art url and puts it in the cache
*
* @param url The url
*/
private static void fetchUrl(URL url) {
//We need the disk cache for this
if (diskCache == null) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!");
return;
}
if (ConnectivityManagerCompat.isActiveNetworkMetered(connectivityManager)) {
//Only download art on unmetered networks (wifi etc.)
return;
}
//Only fetch an URL if we're not fetching it already
if (fetchUrlList.contains(url) || isFetchingList.contains(url)) {
return;
}
fetchUrlList.add(url);
initiateFetch();
}
private static final class FetchURLTask extends AsyncTask<Void, Void, Boolean> {
private final URL url;
private NetworkPacket.Payload payload;
private final DiskLruCache.Editor cacheItem;
private OutputStream output;
/**
* Initialize an url fetch
*
* @param url The url being fetched
* @param payload A NetworkPacket Payload (if from the connected device). null if fetched from http(s)
* @param cacheItem The disk cache item to edit
*/
FetchURLTask(URL url, NetworkPacket.Payload payload, DiskLruCache.Editor cacheItem) throws IOException {
this.url = url;
this.payload = payload;
this.cacheItem = cacheItem;
output = cacheItem.newOutputStream(0);
}
/**
* Opens the http(s) connection
*
* @return True if succeeded
*/
private InputStream openHttp() throws IOException {
//Default android behaviour does not follow https -> http urls, so do this manually
if (!url.getProtocol().equals("http") && !url.getProtocol().equals("https")) {
throw new AssertionError("Invalid url: not http(s) in background album art fetch");
}
URL currentUrl = url;
HttpURLConnection connection;
for (int i = 0; i < 5; ++i) {
connection = (HttpURLConnection) currentUrl.openConnection();
connection.setConnectTimeout(10000);
connection.setReadTimeout(10000);
connection.setInstanceFollowRedirects(false);
switch (connection.getResponseCode()) {
case HttpURLConnection.HTTP_MOVED_PERM:
case HttpURLConnection.HTTP_MOVED_TEMP:
String location = connection.getHeaderField("Location");
location = URLDecoder.decode(location, "UTF-8");
currentUrl = new URL(currentUrl, location); // Deal with relative URLs
//Again, only support http(s)
if (!currentUrl.getProtocol().equals("http") && !currentUrl.getProtocol().equals("https")) {
return null;
}
connection.disconnect();
continue;
}
//Found a non-redirecting connection, so do something with it
return connection.getInputStream();
}
return null;
}
@Override
protected Boolean doInBackground(Void... params) {
//See if we need to open a http(s) connection here, or if we use a payload input stream
try (InputStream input = payload == null ? openHttp() : payload.getInputStream()) {
if (input == null) {
return false;
}
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = input.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
output.flush();
output.close();
return true;
} catch (IOException e) {
return false;
} finally {
if (payload != null) {
payload.close();
}
}
}
@Override
protected void onPostExecute(Boolean success) {
try {
if (success) {
cacheItem.commit();
} else {
cacheItem.abort();
}
} catch (IOException e) {
success = false;
Log.e("KDE/Mpris/AlbumArtCache", "Problem with the disk cache", e);
}
if (success) {
//Now it's in the disk cache, the getAlbumArt() function should be able to read it
//So notify the mpris plugins of the fetched art
for (MprisPlugin mpris : registeredPlugins) {
mpris.fetchedAlbumArt(url.toString());
}
} else {
//Mark the fetch as failed in the memory cache
MemoryCacheItem cacheItem = new MemoryCacheItem();
cacheItem.failedFetch = true;
cacheItem.albumArt = null;
memoryCache.put(url.toString(), cacheItem);
}
//Remove the url from the fetching list
isFetchingList.remove(url);
//Fetch the next url (if any)
--numFetching;
initiateFetch();
}
}
/**
* Does the actual fetching and makes sure only not too many fetches are running at the same time
*/
private static void initiateFetch() {
if (numFetching >= 2) return;
if (fetchUrlList.isEmpty()) return;
//Fetch the last-requested url first, it will probably be needed first
URL url = fetchUrlList.get(fetchUrlList.size() - 1);
//Remove the url from the to-fetch list
fetchUrlList.remove(url);
if ("file".equals(url.getProtocol())) {
throw new AssertionError("Not file urls should be possible here!");
}
//Download the album art ourselves
++numFetching;
//Add the url to the currently-fetching list
isFetchingList.add(url);
try {
DiskLruCache.Editor cacheItem = diskCache.edit(urlToDiskCacheKey(url.toString()));
if (cacheItem == null) {
Log.e("KDE/Mpris/AlbumArtCache",
"Two disk cache edits happened at the same time, should be impossible!");
--numFetching;
return;
}
//Do the actual fetch in the background
new FetchURLTask(url, null, cacheItem).execute();
} catch (IOException e) {
Log.e("KDE/Mpris/AlbumArtCache", "Problems with the disk cache", e);
--numFetching;
}
}
/**
* The disk cache requires mostly alphanumeric characters, and at most 64 characters.
* So hash the url to get a valid key
*
* @param url The url
* @return A valid disk cache key
*/
private static String urlToDiskCacheKey(String url) {
MessageDigest hasher;
try {
hasher = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
//Should always be available
throw new AssertionError(e);
}
StringBuilder builder = new StringBuilder();
for (byte singleByte : hasher.digest(url.getBytes())) {
builder.append(String.format("%02x", singleByte));
}
return builder.toString();
}
/**
* Transfer an asked-for album art payload to the disk cache.
*
* @param albumUrl The url of the album art (should be a file:// url)
* @param payload The payload input stream
*/
static void payloadToDiskCache(String albumUrl, NetworkPacket.Payload payload) {
//We need the disk cache for this
if (payload == null) {
return;
}
if (diskCache == null) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!");
payload.close();
return;
}
URL url;
try {
url = new URL(albumUrl);
} catch (MalformedURLException e) {
//Shouldn't happen (checked on receival of the url), but just to be sure
payload.close();
return;
}
if (!"file".equals(url.getProtocol())) {
//Shouldn't happen (otherwise we wouldn't have asked for the payload), but just to be sure
payload.close();
return;
}
//Only fetch the URL if we're not fetching it already
if (isFetchingList.contains(url)) {
payload.close();
return;
}
//Check if we already have this art
try {
if (memoryCache.get(albumUrl) != null || diskCache.get(urlToDiskCacheKey(albumUrl)) != null) {
payload.close();
return;
}
} catch (IOException e) {
Log.e("KDE/Mpris/AlbumArtCache", "Disk cache problem!", e);
payload.close();
return;
}
//Add it to the currently-fetching list
isFetchingList.add(url);
++numFetching;
try {
DiskLruCache.Editor cacheItem = diskCache.edit(urlToDiskCacheKey(url.toString()));
if (cacheItem == null) {
Log.e("KDE/Mpris/AlbumArtCache",
"Two disk cache edits happened at the same time, should be impossible!");
--numFetching;
payload.close();
return;
}
//Do the actual fetch in the background
new FetchURLTask(url, payload, cacheItem).execute();
} catch (IOException e) {
Log.e("KDE/Mpris/AlbumArtCache", "Problems with the disk cache", e);
--numFetching;
}
}
}

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src/org/kde/kdeconnect/Plugins/MprisPlugin/AlbumArtCache.kt Normal file
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/*
* Copyright 2017 Matthijs Tijink <matthijstijink@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License or (at your option) version 3 or any later version
* accepted by the membership of KDE e.V. (or its successor approved
* by the membership of KDE e.V.), which shall act as a proxy
* defined in Section 14 of version 3 of the license.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.kde.kdeconnect.Plugins.MprisPlugin
import android.content.Context
import android.content.pm.PackageManager.NameNotFoundException
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.net.ConnectivityManager
import android.util.Log
import androidx.collection.LruCache
import androidx.core.content.getSystemService
import androidx.core.net.ConnectivityManagerCompat
import com.jakewharton.disklrucache.DiskLruCache
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import org.kde.kdeconnect.NetworkPacket.Payload
import java.io.File
import java.io.IOException
import java.io.InputStream
import java.net.HttpURLConnection
import java.net.MalformedURLException
import java.net.URL
import java.net.URLDecoder
import java.security.MessageDigest
import java.util.*
/**
* Handles the cache for album art
*/
internal object AlbumArtCache {
/**
* An in-memory cache for album art bitmaps. Holds at most 10 entries (to prevent too much memory usage)
* Also remembers failure to fetch urls.
*/
private val memoryCache = LruCache<String, MemoryCacheItem>(10)
/**
* An on-disk cache for album art bitmaps.
*/
private lateinit var diskCache: DiskLruCache
/**
* Used to check if the connection is metered
*/
private lateinit var connectivityManager: ConnectivityManager
/**
* A list of urls yet to be fetched.
*/
private val fetchUrlList = ArrayList<URL>()
/**
* A list of urls currently being fetched
*/
private val isFetchingList = ArrayList<URL>()
/**
* A integer indicating how many fetches are in progress.
*/
private var numFetching = 0
/**
* A list of plugins to notify on fetched album art
*/
private val registeredPlugins = ArrayList<MprisPlugin>()
/**
* Initializes the disk cache. Needs to be called at least once before trying to use the cache
*
* @param context The context
*/
@JvmStatic
fun initializeDiskCache(context: Context) {
if (this::diskCache.isInitialized) return
val cacheDir = File(context.cacheDir, "album_art")
val versionCode: Int
try {
val info = context.packageManager.getPackageInfo(context.packageName, 0)
versionCode = info.versionCode
//Initialize the disk cache with a limit of 5 MB storage (fits ~830 images, taking Spotify as reference)
diskCache = DiskLruCache.open(cacheDir, versionCode, 1, 1000 * 1000 * 5.toLong())
} catch (e: NameNotFoundException) {
throw AssertionError(e)
} catch (e: IOException) {
Log.e("KDE/Mpris/AlbumArtCache", "Could not open the album art disk cache!", e)
}
connectivityManager = context.applicationContext.getSystemService()!!
}
/**
* Registers a mpris plugin, such that it gets notified of fetched album art
*
* @param mpris The mpris plugin
*/
@JvmStatic
fun registerPlugin(mpris: MprisPlugin) {
registeredPlugins.add(mpris)
}
/**
* Deregister a mpris plugin
*
* @param mpris The mpris plugin
*/
@JvmStatic
fun deregisterPlugin(mpris: MprisPlugin?) {
registeredPlugins.remove(mpris)
}
/**
* Get the album art for the given url. Currently only handles http(s) urls.
* If it's not in the cache, will initiate a request to fetch it.
*
* @param albumUrl The album art url
* @return A bitmap for the album art. Can be null if not (yet) found
*/
@JvmStatic
fun getAlbumArt(albumUrl: String?, plugin: MprisPlugin, player: String?): Bitmap? {
//If the url is invalid, return "no album art"
if (albumUrl.isNullOrEmpty()) {
return null
}
val url = try {
URL(albumUrl)
} catch (e: MalformedURLException) {
//Invalid url, so just return "no album art"
//Shouldn't happen (checked on receival of the url), but just to be sure
return null
}
//We currently only support http(s) and file urls
if (url.protocol !in arrayOf("http", "https", "file")) {
return null
}
//First, check the in-memory cache
val albumItem = memoryCache[albumUrl]
if (albumItem != null) {
//Do not retry failed fetches
return if (albumItem.failedFetch) {
null
} else {
albumItem.albumArt
}
}
//If not found, check the disk cache
if (!this::diskCache.isInitialized) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!")
return null
}
try {
val item = diskCache[urlToDiskCacheKey(albumUrl)]
if (item != null) {
val result = BitmapFactory.decodeStream(item.getInputStream(0))
item.close()
val memItem = MemoryCacheItem()
if (result != null) {
memItem.failedFetch = false
memItem.albumArt = result
} else {
//Invalid bitmap, so remember it as a "failed fetch" and remove it from the disk cache
memItem.failedFetch = true
memItem.albumArt = null
diskCache.remove(urlToDiskCacheKey(albumUrl))
Log.d("KDE/Mpris/AlbumArtCache", "Invalid image: $albumUrl")
}
memoryCache.put(albumUrl, memItem)
return result
}
} catch (e: IOException) {
return null
}
/* If not found, we have not tried fetching it (recently), or a fetch is in-progress.
Either way, just add it to the fetch queue and starting fetching it if no fetch is running. */
if ("file" == url.protocol) {
//Special-case file, since we need to fetch it from the remote
if (url in isFetchingList) return null
if (!plugin.askTransferAlbumArt(albumUrl, player)) {
//It doesn't support transferring the art, so mark it as failed in the memory cache
memoryCache.put(url.toString(), MemoryCacheItem(true))
}
} else {
fetchUrl(url)
}
return null
}
/**
* Fetches an album art url and puts it in the cache
*
* @param url The url
*/
private fun fetchUrl(url: URL) {
//We need the disk cache for this
if (!this::diskCache.isInitialized) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!")
return
}
if (ConnectivityManagerCompat.isActiveNetworkMetered(connectivityManager)) {
//Only download art on unmetered networks (wifi etc.)
return
}
//Only fetch an URL if we're not fetching it already
if (url in fetchUrlList || url in isFetchingList) {
return
}
fetchUrlList.add(url)
initiateFetch()
}
/**
* Does the actual fetching and makes sure only not too many fetches are running at the same time
*/
private fun initiateFetch() {
if (numFetching >= 2 || fetchUrlList.isEmpty()) return
//Fetch the last-requested url first, it will probably be needed first
val url = fetchUrlList.last()
//Remove the url from the to-fetch list
fetchUrlList.remove(url)
if ("file" == url.protocol) {
throw AssertionError("Not file urls should be possible here!")
}
//Download the album art ourselves
++numFetching
//Add the url to the currently-fetching list
isFetchingList.add(url)
try {
val cacheItem = diskCache.edit(urlToDiskCacheKey(url.toString()))
if (cacheItem == null) {
Log.e("KDE/Mpris/AlbumArtCache",
"Two disk cache edits happened at the same time, should be impossible!")
--numFetching
return
}
//Do the actual fetch in the background
GlobalScope.launch { fetchURL(url, null, cacheItem) }
} catch (e: IOException) {
Log.e("KDE/Mpris/AlbumArtCache", "Problems with the disk cache", e)
--numFetching
}
}
/**
* The disk cache requires mostly alphanumeric characters, and at most 64 characters.
* So hash the url to get a valid key
*
* @param url The url
* @return A valid disk cache key
*/
private fun urlToDiskCacheKey(url: String): String {
return MessageDigest.getInstance("MD5").digest(url.toByteArray())
.joinToString(separator = "") { String.format("%02x", it) }
}
/**
* Transfer an asked-for album art payload to the disk cache.
*
* @param albumUrl The url of the album art (should be a file:// url)
* @param payload The payload input stream
*/
@JvmStatic
fun payloadToDiskCache(albumUrl: String, payload: Payload?) {
//We need the disk cache for this
if (payload == null) {
return
}
if (!this::diskCache.isInitialized) {
Log.e("KDE/Mpris/AlbumArtCache", "The disk cache is not intialized!")
payload.close()
return
}
val url = try {
URL(albumUrl)
} catch (e: MalformedURLException) {
//Shouldn't happen (checked on receival of the url), but just to be sure
payload.close()
return
}
if ("file" != url.protocol) {
//Shouldn't happen (otherwise we wouldn't have asked for the payload), but just to be sure
payload.close()
return
}
//Only fetch the URL if we're not fetching it already
if (url in isFetchingList) {
payload.close()
return
}
//Check if we already have this art
try {
if (memoryCache[albumUrl] != null || diskCache[urlToDiskCacheKey(albumUrl)] != null) {
payload.close()
return
}
} catch (e: IOException) {
Log.e("KDE/Mpris/AlbumArtCache", "Disk cache problem!", e)
payload.close()
return
}
//Add it to the currently-fetching list
isFetchingList.add(url)
++numFetching
try {
val cacheItem = diskCache.edit(urlToDiskCacheKey(url.toString()))
if (cacheItem == null) {
Log.e("KDE/Mpris/AlbumArtCache",
"Two disk cache edits happened at the same time, should be impossible!")
--numFetching
payload.close()
return
}
//Do the actual fetch in the background
GlobalScope.launch { fetchURL(url, payload, cacheItem) }
} catch (e: IOException) {
Log.e("KDE/Mpris/AlbumArtCache", "Problems with the disk cache", e)
--numFetching
}
}
private class MemoryCacheItem(var failedFetch: Boolean = false, var albumArt: Bitmap? = null)
/**
* Initialize an url fetch
*
* @param url The url being fetched
* @param payload A NetworkPacket Payload (if from the connected device). null if fetched from http(s)
* @param cacheItem The disk cache item to edit
*/
private suspend fun fetchURL(url: URL, payload: Payload?, cacheItem: DiskLruCache.Editor) {
var success = withContext(Dispatchers.IO) {
//See if we need to open a http(s) connection here, or if we use a payload input stream
val output = cacheItem.newOutputStream(0)
try {
val inputStream = payload?.inputStream ?: openHttp(url)
val buffer = ByteArray(4096)
var bytesRead: Int
if (inputStream != null) {
while (inputStream.read(buffer).also { bytesRead = it } != -1) {
output.write(buffer, 0, bytesRead)
}
}
output.flush()
output.close()
return@withContext true
} catch (e: IOException) {
return@withContext false
} finally {
payload?.close()
}
}
try {
// Since commit() and abort() are blocking calls, they have to be executed in the IO
// dispatcher.
withContext(Dispatchers.IO) {
if (success) {
cacheItem.commit()
} else {
cacheItem.abort()
}
}
} catch (e: IOException) {
success = false
Log.e("KDE/Mpris/AlbumArtCache", "Problem with the disk cache", e)
}
if (success) {
//Now it's in the disk cache, the getAlbumArt() function should be able to read it
//So notify the mpris plugins of the fetched art
for (mpris in registeredPlugins) {
mpris.fetchedAlbumArt(url.toString())
}
} else {
//Mark the fetch as failed in the memory cache
memoryCache.put(url.toString(), MemoryCacheItem(true))
}
//Remove the url from the fetching list
isFetchingList.remove(url)
//Fetch the next url (if any)
--numFetching
initiateFetch()
}
/**
* Opens the http(s) connection
*
* @return True if succeeded
*/
private fun openHttp(url: URL): InputStream? {
//Default android behaviour does not follow https -> http urls, so do this manually
if (url.protocol !in arrayOf("http", "https")) {
throw AssertionError("Invalid url: not http(s) in background album art fetch")
}
var currentUrl = url
var connection: HttpURLConnection
loop@ for (i in 0..4) {
connection = currentUrl.openConnection() as HttpURLConnection
connection.connectTimeout = 10000
connection.readTimeout = 10000
connection.instanceFollowRedirects = false
when (connection.responseCode) {
HttpURLConnection.HTTP_MOVED_PERM, HttpURLConnection.HTTP_MOVED_TEMP -> {
var location = connection.getHeaderField("Location")
location = URLDecoder.decode(location, "UTF-8")
currentUrl = URL(currentUrl, location) // Deal with relative URLs
//Again, only support http(s)
if (currentUrl.protocol !in arrayOf("http", "https")) {
return null
}
connection.disconnect()
continue@loop
}
}
//Found a non-redirecting connection, so do something with it
return connection.inputStream
}
return null
}
}